Multipotent Dental Stem Cells: An Alternative Adult Derived Stem Cell Source for Regenerative Medicine

Abstract

The pluripotent nature of embryonic stem cells (ESCs) makes them amenable for regenerative therapies because they can differentiate into cells that form all tissue types within the body (Zandstra and Nagy, 2001). The potential drawbacks to the use of ESCs for cellular therapies include the obvious ethical dilemmas of obtaining ESCs, the potential of cancer or tumor formation and the risk of immunogenic rejection (Wobus and Boheler, 2005). Therefore adult stem cell sources with multipotent and pluripotent potential have been sought as an alternative for ESCs including mesenchymal stem cell (MSCs) and tissuederived specific stem cells. Interestingly, the isolation of a population of dental stem cells derived ectodermally from the neural crest (NC) have been shown to be multipotent and give rise to multifarious cell types that result in the development of many of the body’s organs or tissues (Huang et al., 2009a; Huang et al., 2009b). Stem cells extracted from dental tissues including dental pulp, periodontal ligament, apical papilla and dental follicle precursor cells have an expansive differentiation potential with respect to mesodermal and ectodermal lineages. Currently there are six types of dental stem cells that are well characterized and described both in vitro and in vivo (Gronthos et al., 2000; Huang et al., 2009a; Karaoz et al., 2010; Miura et al., 2003; Morsczeck et al., 2005; Seo et al., 2004; Sonoyama et al., 2006). Some dental stem cells lines have been shown to express ESC markers Oct4, Nanog, Sox2 and Klf4 and NC markers p75, Sox10, Slug and Nestin suggesting that dental stem cells may be able to become many of the same tissues as ESCs (Huang et al., 2009a). Further, dental stem cells have been shown to differentiate into neurogenic, adipogenic, cardiomyogenic, chondrogenic, myogenic and osteogenic lineages (Huang et al., 2009a; Karaoz et al., 2010; Miura et al., 2003; Seo et al., 2004; Sonoyama et al., 2006; Zhang et al., 2006). Since dental stem cells have been shown to differentiate into a multitude of cell types, their potential for use in tissue regeneration may be boundless. We are currently using dental stem cells to investigate the mechanisms of mechanotransduction elicited during dynamic cyclic compression for chondrogenesis. Our long term goal is to develop technology and protocols utilizing dental stem cells and biomechanical force for reparative medicine and tissue regeneration of cartilage. This review